1. Field of the Invention
The present invention relates to a method for manufacturing a silicon-on-insulator (SOI) substrate having a so-called SOI structure in which a semiconductor layer is provided on an insulating surface, and a method for manufacturing semiconductor device having an SOI structure.
2. Description of the Related Art
Integrated circuits have been developed, which use a semiconductor substrate called a silicon-on-insulator (hereinafter also referred to as an SOI) that has a thin single crystal semiconductor layer over an insulating surface, instead of a silicon wafer that is manufactured by thinly slicing an ingot of a single crystal semiconductor. An integrated circuit using an SOI substrate has been attracting attention because parasitic capacitance between drains of the transistors and the substrate is reduced and the performance of the semiconductor integrated circuit is improved.
As a method for manufacturing SOI substrates, a hydrogen ion implantation separation method is known (for example, see Patent Document 1: Japanese Published Patent Application No. 2000-124092). The hydrogen ion implantation separation method is a method in which hydrogen ions are implanted into a silicon wafer to form a damaged layer at a predetermined depth from a surface of the silicon wafer, and the silicon wafer is separated at the damaged layer, whereby a thin silicon layer is bonded to another silicon wafer. In addition to the heat treatment for separation of a silicon layer, it is necessary to perform heat treatment in an oxidizing atmosphere to form an oxide film over the silicon layer, remove the oxide film, and perform heat treatment at 1000° C. to 1300° C. to increase bonding strength.
On the other hand, a semiconductor device in which an insulating substrate such as high heat resistance glass substrate is provided with a silicon layer is disclosed (e.g., see Reference 2: Japanese Published Patent Application No. H11-163363). This semiconductor device has a structure in which the entire surface of crystallized glass having a distortion point of greater than or equal to 750° C. is protected by an insulating silicon film and a silicon layer obtained by a hydrogen ion implantation separation method is attached onto the insulating silicon film.